Solving Partial Fractions with Integration

[nameVoid]

$$\int \frac{x^2+3x+1}{x^4+5x^2+4}$$
$$(Ax+B)(x^2+1)+(Cx+D)(x^2+4)$$
letting x=0 ..B+4D=1 not sure of the next move

 

[tiny-tim]

Hi nameVoid!

letting x=0 ..B+4D=1 …

That's fine.

Now equate the coefficients of x, and then the coefficients of x², and then the coefficients of x³.